Re: [PATCH 9/9] arm64: dts: imx95: Describe Mali G310 GPU

Frank Li
2025-02-27T21:28:06Z

On Thu, Feb 27, 2025 at 09:36:55PM +0100, Marek Vasut wrote:
> On 2/27/25 6:43 PM, Frank Li wrote:
> [...]
>
> > > diff --git a/arch/arm64/boot/dts/freescale/imx95.dtsi b/arch/arm64/boot/dts/freescale/imx95.dtsi
> > > index 3af13173de4bd..36bad211e5558 100644
> > > --- a/arch/arm64/boot/dts/freescale/imx95.dtsi
> > > +++ b/arch/arm64/boot/dts/freescale/imx95.dtsi
> > > @@ -249,6 +249,37 @@ dummy: clock-dummy {
> > > clock-output-names = "dummy";
> > > };
> > >
> > > + gpu_fixed_reg: fixed-gpu-reg {
> > > + compatible = "regulator-fixed";
> > > + regulator-min-microvolt = <920000>;
> > > + regulator-max-microvolt = <920000>;
> > > + regulator-name = "vdd_gpu";
> > > + regulator-always-on;
> > > + regulator-boot-on;
> >
> > Does really need regulator-boot-on and regulator-always-on ?
>
> I don't think so, this is a development remnant, fixed, thanks.
>
> [...]
>
> > > + gpu: gpu@4d900000 {
> > > + compatible = "fsl,imx95-mali", "arm,mali-valhall-csf";
> > > + reg = <0 0x4d900000 0 0x480000>;
> > > + clocks = <&scmi_clk IMX95_CLK_GPU>;
> > > + clock-names = "core";
> > > + interrupts = <GIC_SPI 288 IRQ_TYPE_LEVEL_HIGH>,
> > > + <GIC_SPI 289 IRQ_TYPE_LEVEL_HIGH>,
> > > + <GIC_SPI 290 IRQ_TYPE_LEVEL_HIGH>;
> > > + interrupt-names = "gpu", "job", "mmu";
> > > + mali-supply = <&gpu_fixed_reg>;
> > > + operating-points-v2 = <&gpu_opp_table>;
> > > + power-domains = <&scmi_devpd IMX95_PD_GPU>, <&scmi_perf IMX95_PERF_GPU>;
> > > + power-domain-names = "mix", "perf";
> > > + resets = <&gpu_blk_ctrl 0>;
> > > + #cooling-cells = <2>;
> > > + dynamic-power-coefficient = <1013>;
> > > + status = "disabled";
> >
> > GPU is internal module, which have not much dependence with other module
> > such as pinmux. why not default status is "disabled". Supposed gpu driver
> > will turn off clock and power if not used.
> My thinking was that there are MX95 SoC with GPU fused off, hence it is
> better to keep the GPU disabled in DT by default. But I can also keep it
> enabled and the few boards which do not have MX95 SoC with GPU can
> explicitly disable it in board DT.
>
> What do you think ?

GPU Fuse off should use access-control, see thread
https://lore.kernel.org/imx/20250207120213.GD14860@localhost.localdomain/

Frank